Method of treating animal tissue and products obtained therefrom



Patented Mar. 22, 1 927.

UNITED STATES PATENT OFFICE.

FRIEDRICH WILHELM WE ER, or HACKENSACK, NEW JERSEY, assrenon TO' MAY- woon onnmroar. wonxs, or MAYWOOD, NEW J RSE A CORPORATION on NEW JERSEY.

' METHOD OF TREATING ANIMAL TISSUE AND, PRODUCTS OBTAINED THEREFROM.

No Drawing. Application filed April 1, 1924, Serial No. 704,282. Renewed August 6, 1 926.-

This invention relatesto certain products obtained from animal tissue, for instance animal hides in their dehaired state as well as with their natural hair growth thereon;

it furthermore relatesto a tanning process applying solutions of compounds of the rare earth metals as a tanning agent.

It is anobject of the invention to prov de a process furnishing a leather of super or l0 whiteness and of unusual lasting properties. i It is another object of the invention to provide a process by which a bettenquahty of leather can be produced with considerable economical advantages. It is a further object of the invention to provide a pr ocess which dispenses with the alum on account of its well known shortcomings and furnishes at a low cost an even better leather than that obtained with alum; It) In the resent art'of tanning the'utilization of aliim playsa great part though it has considerable shortcomings because it contains a high amount of acid as is illustrated by its formula Al (SO l'-24H O, which ,5 shows that in view. of the low atomic weight of aluminum the percentage of acidin the molecule of alum is enormously high; though the alum is classed among'the low priced heavy chemicals its cost for the pur- 80' poses of the-manufacture of. leather is by no means low as the alum must be "deprivedat the tannery of its iron content before it can be applied for tanning; also the considerablefrelght charges its great amount of 85 Water of crystallization are a burdensome and useless expense. The unusually high proportion of acid i the alum requiress a. considerable amount 9 kali to neutral it; I it is also possible t 1 40 tanning process, ap agent, Wlll retain sulfu ter cellularspacesso 1'. v I} the tissue and in the course of time will on the leather andwill render it brittle; such .46 leather will then easily crumble to pieces on handling it.

Notwithstanding such considerable shortcomingsalum is yet applied. on a large scale for tanning urposes because it has been found very iificult to find a stitute for same,

i I foundthat proper sub-' I have now found that the compounds of the rare earth metals readily act as tanning agents as far as the qualityof the leather and the cost of its production is concerned.

Notwithstanding the relatively high price which the compounds of the rare earth metals usually obtain on the market on ac count of the high price of the rawmaterial, the leather obtained by my new tanning process based on the application of the com pounds of the rare earth metals is produced at such a low cost that it can successfully compete with the leather produced by any other process. It is probably due to the low solubility of the sulfates of the rare earth metals and of the double salts formed by same, that the rare eartlr metals were not. considered as suitable tanning agents; another reason was also that the rare earth metal compounds offered on the market for other purposes were actually too high in price to admit even of the thought of using them as tanning agents. Nor did the other sources of raw materiaL'from which such compounds could be drawn, present themselves in such form as to suggest the proposition of rendering them available'for tanning purposes, but the economical situation in the manufacture ofchemicals for incandescent gas light has greatly changed with the enormous progress of the electric light and confronts the manufacturers of such I chemicals with new problems. In 'my efforts of extracting the values contained in monazite sand and in the residue obtained in the manufacture of compounds for impregnating the-mantles for incandescent gas light e rare earth metal compounds derived from these materials acted as excellent tanning agents in every respect and in some'points are even superior to any other such agent as will be more thoroughlypointed out hereinafter.

For the better understanding of my in- .ventionIv-referto the fact that in the tannage withalum a certain amount of sodium chloridp'is added; practical tanners maintain tli aiton account of its hygroscopity the sodium chloride in the animal tissue later on softens tl e 's-ame after it has passed the tan ning process. On the other side it is claimed that the addition of .sodium chloride to a tannlng liquor containipg aluminum sulfate causes a double decomposition to take place which results in the formation of of which the Alcl is supposed to act as they both cases the desired coagulate can only be olzgtained upon the addition of sodium chlor1 e.

I have now found that upon the addition of a concentrated sodium chloride solution, for instance a 10% solution, to a 5% solution of the basic acetates of a mixture of the rare earth metals a strong smell of acetic acid is noticed as soon as the animal tissue is introduced into the combined solutions, but no coagulation takes place. The animal tissue or hide, however, is thoroughly penetrated and a deposition of rare earth metal compounds practically free of acid takes place in the intercellular spaces; while the hide is dried, acetic acid is still evaporating and the leather finally obtained appears perfectly white.

I have furthermore found that I can sterilize the hides by acting on the same with the salts of the rare earth metals mentioned above. This is important because the sterilization of the hides prevents their destruction by the putrefaction caused by the organic matter, like flesh particles, blood etc, adhering to the hides; on the other side it is very important that this sterilization be effected with materials which are not detrimental to the hides nor to the people who are using the manufactures made from the sterilized leather.

' product.

For instance formaldehyde is very eflective in preventing putrefaction, but it is highly injurious to the leather as well as to the wearer of the leather Ihave now found. that I can accomplish the sterilizatiol'rof the hides most satisfactorily in every respect byv the action of the rare earth metal salts referred to and applied to the leather by the processes described above. I have especially found that leathers tanned by these processes are distinguished by being proofto mildew; this is strikingly shown by the following test which consisted in moistening leather, having been tanned by any of the above processes, with water and subsequently drying it .in an open pan at a temperature slightly above that of the atmosphere, and continumg these operations alternately for 22 weeks without generating even the slightest trace of mildew. It is obvious therefore, ,that leather, obtained by any of my processes described above, is especially suitable for leather goods intended to be used in tropic climates where the heat and the enor mous amount of moisture in the air combine to thoroughly cover goods, made from leather tanned by other than my processes,

in a few days with a layer of mildew.

This tannage may also be obtained in the following manner:

The best 'socalled French kid leather, famous for its whiteness and softness as well as for its elasticity,-was up to now thought possible only by working the hides in a drum with a semiliquid paste of a mixture of aluminum sulfate with wheat flour, eggyolk sodium chloride and warm water at the temperature of approximately 37 deg. C. The aluminum sulfate was known to have the disadvantage already metioned above and many efforts to substitute said aluminum sulfate were always accompanied by a negative result. It was especially the traces of acid retained by the animal tissue which were felt very keenly because such leather had a tendency to be brittle and occasionally displayed rust spots which were caused by the retained acid when the leather came into contact with iron, the exudations of the animal tissue, including valerianic and butyric acid, in the presence of sodium chloride favoring the formation of such rust spots, or eventually spots caused by other metals. In my new tanning process I can produce a leather which is superior to the socalled French kid leather by treating, preferably at 37 deg. C., the prepared hides with a solution of the acetates of the rare earth metals to which the usual quantity of eg yolk, wheat flour and sodium chloride has been added. As the applied compounds of the rare earth metals are free of sulfuric acid as well as of the slightest trace of iron, the leather obtained by my new process is of superior softness and elasticity as well as of permanent whitenesss.

This result was rather unexpected as experiments with salts containing a proportionately great quantity of cerous chloride, (3e01,, yielded an unsatisfactory leatherv owing to its yellow color and its poor tan- .ning. From a long line of experiments I have found that the cause of this is the continuous alternate change of the cerousoxide the destruction of -the skin. This undesirable feature is, however, entirely avoided by the application of the acetates of the rare earth metals; 1 have observed in my work by the same in the skin is very much more stable and gives a leather of great durability lower state of oxidation as undoubtedly.

occurs with a great deteriorating effect on the hide treated with a solution containing cerium chloride.'

For the reason that the atomic weights of the rare earth metals are very high as compared with that of aluminum, a reater quantity of the same will combine with the animal tissue and will therefore give the leather a greater whiteness than can be accomplished with compounds of lower atomic weight. As the quantity of acid in the molecule of the rare earth metal compounds is proportionately smaller than in the compounds of metals of low.atomic weight, the

- in connection with my new tanning process amountof acid to produce the neutral salt, or'the amount of alkali to turn such a salt into a basic salt is less, regardless of whether the salt be a sulfate, chloride or acetate, and the cost of the materials to perform these changes is smaller than with the other chemicals applied up to now as tanning agents. Moreover, as the-compounds used are produced preferably from the waste products obtained in the manufacture of the salts for.the impregnation of mantles for incandescent gas light, this fact in combination with the favorable circumstances pointed out above make it selfevident that my new tanning process can successfully compete as toec'onomy as well as quality of products with any of the ,old tanmng processes working even with such apparently low priced materials as alum.

Though in theafar greater majority of cases my new tanning process will "be applied to hides dehaired and bated-in the usual ways I wish to state that my new invention can just as wellbe'ap lied ,tojpelts preserved in their natural hair cover. In the preparation'of furs the pelts are usually wetted on the flesh-side with a solution of sulfuric acid and sodium chloride and are subsequently worked with butter andsawdust whereby soft furs are obtained which, however, present little resistance to morsture and heat. I have now found that wet-. ting a pelt on the flesh side with-a solution of acetates-of rare earth metals, including cerium, yields a soft and better keeping fur,

especially if the fur after the treatment with the above mentioned rare earth metal-- acet ates'is finished by working it with fats, oils,

or butter and 'sawdust.-

' I wish furthermore to state that the rare earth metal compounds in the leather as well as in the fur act as a mordant to the fiber and that the material treated with same can be dyed with a great variety of shades,-'

giving to the leather a bright and rich appearance and to the-furs the much desired lustre.

What I claim is:

1. The process-of treating animal tissue, comprising acting in the presence of. sodium chloride upon the tissue, prepared in any of the well known ways, w1th a solution .of

a salt of a rare earth metal capable of forming a basicsalt. 7

2. The process oftreating animal tissue, comprising acting in the presence of sodium chloride upon the tissue, prepared in any of the well known ways, w1th a solution of a salt. formed by a volatile acid with any of the rare earth metals.

3. The process of treating animal tissue, comprising acting in the presence of sodium chloride upon the tissue, prepared in any of the well known ways, with asolution of an 'acetate of any of the rare earth metals.

4..T he process of treating animal tissue, COIIlPl'lSlIlg acting'in the presence of sodium chloride upon the tissue, prepared inany of the well known ways, with a solution of a basic acetate of any of the rare earth metals.

:5. The process of treating animal tissue, comprising acting upon the tissue, prepared in any of the well known ways, in the presence of sodium chloride with asolution of the salts of a plurality of rare earth metals capable of forming basic salts.

6. The process of treating animal tissue, comprising acting upon the tissue, repared in any of the well known ways, with 7. The process of treating animal tissue,

comprising acting upon the tissue, prepared in any of the-usual ways, with a solutlon of acetates of the rare earth metals in the presence of egg-yolk, flour and sodiumchloride.

8. The process of treating animal tissue, comprising acting upon the tissue, prepared in any of the usual ways, at approximately- 37 deg. C. with a solution of acetates of the rare earth metals in the presence of egg-yolk, flour and sodium chloride.

9. The process of treating animaltissue, comprising acting at the flesh side of the tis sue by wetting same with a solution of sodium chloride and a salt of rare earth metal.

10. The process of treating animal tissue, comprising acting at the flesh side of the tissue by wetting same with a .solution of sodium chloride and an acetate of a rare earth 'metal' and then working the tissue thus a 10% solution of sodium' chloride and a 5% solution of the basic acetates of rare earth metals.

treated with a fat and a vegetable mass like saw-dust.

11. As a new article of manufacture, a leather being substantially free of acid and having an oxide of a rare earth metal depos ited in an inert state in its tissue.

.12. As a new article of manufacture, a leather being substantially free of acid and having a mixture of inert oxides of rare earth metals deposited in its tissue.

13. The process of sterilizing hides, comprising acting upon the raw hides, from which the flesh particles, or other organic matter, has been removed, with a solution of a salt of a rare earth metal capable of forming a basic salt.

14. The process of sterilizing hides, from which the flesh particles or other organic matter has been removed, said process comprising actlng upon such hides in the presence of sodium chloride with a solution of a salt of a rare earth metal capable of forming a basic salt. I

15. The process of sterilizing hides, comprising acting upon the raw hides, from which the flesh particles, or other organic matter, has been removed, with a solution of sodium chloride and a solution of the basic a solution of ence of egg yolk, flour and sodium chloride.

FRIEDRICH WILHELM 

